3). The diagram below shows growth of E. coli strains 1 through 4 on a variety of media. Small dots indicate NO colony growth. Large dots indicate colony growth. Minimal wO.. 2004 Minimal +Met 1- 0₂/ N Minimal +Arg -00~/ 2004 Minimal +Arg+Met -00₂/ a). Write down the genotypes of strains 1-4. b). Describe how you would screen for methionine auxotrophs using a met+ starting strain.

3). The diagram below shows growth of E. coli strains 1 through 4 on a variety of media. Small dots indicate NO colony growth. Large dots indicate colony growth. Minimal wO.. 2004 Minimal +Met 1- 0₂/ N Minimal +Arg -00~/ 2004 Minimal +Arg+Met -00₂/ a). Write down the genotypes of strains 1-4. b). Describe how you would screen for methionine auxotrophs using a met+ starting strain.

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter17: Bacterial And Viral Genetics

Section: Chapter Questions

Problem 1ITD

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Two auxotrophic triple Escherichia coli strains (A: met- phe- ade- val+ bio+ thr+ and B: met+ phe+ ade+ val- bio- thr-) are mixed in LB liquid medium, diluted and then spread on LB solid rich medium. Six colonies are observed: Then, replicates are performed on 6 different media (minimum medium + glucose + indicated substances). The results are shown below. Determine the genotype of the 6 colonies observed. Which ones are from strain A? From strain B? Which hypotheses can explain these results and which one do you prefer? met phe val bio Abbreviations: met ade val thr phe ade bio thr Met: methionine; Phe: phenylalanine; Ade: adenine; Val: valine; Bio: biotin; Thr: threonine.
In the Avery, McLeod, McCarty Experiment where supernatant from heat killed, virulent S Strain pneumonia solutions were added to non-virulent R Strain pneumonia cell cultures and allowed to grow in liquid media (i.e., broth). In tubes where Protease was added to the supernatant prior to cell culture, what was the observed effect when plating and growing the S. pneumonia cells to solid media? Selected answer will be automatically saved. For keyboard navigation, press up/down arrow keys to select an answer. a b C d e All RNA was degraded and Transformation of the R Strain to S Strain occurred. All Protein was degraded and Transformation of the R Strain to S Strain occurred. All DNA was degraded and Transformation of the R Strain to S Strain occurred. All RNA was degraded and no Transformation occurred indicating RNA is the molecule of Transformation inheritance None of the above are true
3 2. The table below was obtained by P1 phage transduction followed by media selection of an E. coli strain lacking the three genes. Determine the map order of the genes given the information provided. Demonstrate CLEARLY which are closer or farther from each other (no numbers needed). 1 2 MAP: Experiment Selected marker Ala+ Gly+ Ser+ Unselected markers (select- ed for by subsequent plating) 27% Ser+, 2% Gly+ 3% Ser+, 1% Ala+ 35% Ala+, 4% Gly+
A graduate student was assaying LD50 (lethal dose 50%) of two temperature-sensitive Francisella tularensis strains in HeLa cells (human cell line). Both strains can infect humans and cause fatal tularemia if untreated, but it is difficult to obtain LD50 values in human subjects. The data below shows LD50 (lethal dose 50%) values of the strains in human cell culture. Can you predict the more virulent strain of the two human pathogens? Francisella tularensis strain A: LD50 @ 20°C= 100; LD50 @ 37°C= 1000 Francisella tularensis strain B: LD50 @ 20°C= 1000 LD 50 @ 37°C= 100 O It is not possible to determine the virulence of the two strains as human pathogens from the provided data Strain A and strain B are equally virulent as human pathogens, as they average out in virulence. O Strain A is more virulent than strain A as a human pathogen. O Strain B is more virulent than strain A as a human pathogen.
A graduate student was assaying LD50 (lethal dose 50%) of two temperature-sensitive Francisella tularensis strains in HeLa cells (human cell line). Both strains can infect humans and cause fatal tularemia if untreated, but it is difficult to obtain LD50 values in human subjects. The data below shows LD50 (lethal dose 50%) values of the strains in human cell culture. Can you predict the more virulent strain of the two human pathogens? Francisella tularensis strain A: LD50 @ 20∘C= 100; LD50 @ 37∘C= 1000 Francisella tularensis strain B: LD50 @ 20∘C= 1000 LD50 @ 37∘C= 100 Group of answer choices It is not possible to determine the virulence of the two strains as human pathogens from the provided data Strain A and strain B are equally virulent as human pathogens, as they average out in virulence. Strain A is more virulent than strain A as a human pathogen. Strain B is more virulent than strain A as a human pathogen.
In the Avery, McLeod, McCarty Experiment where supernatant from heat killed, virulent S Strain pneumonia solutions were added to non-virulent R Strain pneumonia cell cultures and allowed to grow in liquid media (i.e., broth). In tubes where Protease was added to the supernatant prior to cell culture, what was the observed effect when plating and growing the S. pneumonia cells to solid media?
Consider the five E. coli merodiploid strains listed here. Strain #1 I+P+O+Z-Y+/I+P+OcZ+Y+ Strain #2 I+P+O+Z+Y+/I-P+OcZ+Y- Strain #3 I+P+O+Z-Y+/I-P+OcZ+Y- Strain #4 I-P-O+Z+Y-/I+P+OcZ-Y+ Strain #5: ISP+O+Z+Y+/I-P+O+Z+Y- Which of these strains will be unable to express lactose permease under any conditions? Select all correct answers. A.)Strain #3 B.)Strain #4 C.)Strain #2 D.)Strain #5 E.)Strain #1
Consider the five E. coli merodiploid strains listed here. Strain #1 I+P+O+Z-Y+/I+P+OcZ+Y+ Strain #2 I+P+O+Z+Y+/I-P+OcZ+Y- Strain #3 I+P+O+Z-Y+/I-P+OcZ+Y- Strain #4 I-P-O+Z+Y-/I+P+OcZ-Y+ Strain #5: ISP+O+Z+Y+/I-P+O+Z+Y- Which of these strains will be inducible for expression of b-galactosidase? Select all correct answers. A.) Strain #2 B.) Strain #3 C.) Strain #1 D.) Strain #4 E.) None of these F. )Strain #5
Consider the five E. coli merodiploid strains listed here. Strain #1 I+P+O+Z-Y+/I+P+OcZ+Y+ Strain #2 I+P+O+Z+Y+/I-P+OcZ+Y- Strain #3 I+P+O+Z-Y+/I-P+OcZ+Y- Strain #4 I-P-O+Z+Y-/I+P+OcZ-Y+ Strain #5: ISP+O+Z+Y+/I-P+O+Z+Y- Which of these strains will express b-galactosidase constitutively? Select all correct answers. A.)Strain #5 B.)Strain #1 C.)Strain #4 D.)Strain #2 E.)Strain #3
Considering counting rules, calculate the initial titre of the sample viral stock if the following plaques were counted in a plaque assay. Show clear sample calculations. Table 1: Plaque assay counts for lambda phage stock titre enumeration of average concentration (PFU/mL) Total dilution of viral stock 1/13500000 1/135000000 1/135000000 plated Volume diluted viral stock 0.1 0.1 0.1 plated (mL) PFU replicate 1 TNTC 275 25 Calculated concentration (PFU/mL) replicate 1 PFU replicate 2 TNTC 239 23 Calculated concentration (PFU/mL) replicate 2 Average concentration (PFU/mL)
a. Bacteriophage P22 was used in generalized transduction experiments to infect the Salmonella typhimurium donor strains described in the table below. The resulting phage lysates were then used to infect the S. typhimurium recipient strains listed in the table. In each cross, a phenotype was selected for one of the three genetic markers studied (str, aceA, thrA), and then replicates were performed to select the corresponding recombinants for the other two markers. The results are given in the following table: Recipient strain Selected phenotype Selected recombinants Donor strain str thrA aceAt thrA str aceA+ strs thrA+ aceA thrA+ str aceA Str Ace+ Str ThrA ThrA+ ThrA ThrA+ Ace Ace+ str: gene involved in streptomycin resistance, aceA: gene involved in the use of acetate as a carbon source, thrA: gene involved in the biosynthesis of threonine. Number 60 40 95 5 10 90 What are the selective media used in these three transduction experiments, on the one hand to obtain the selected…
A high cell density culture of recombinant E. coli was carried out according to the following strategy:-Step 1: single batch with exponential growth until 98% conversion of the substrate, starting from V0= 4.0 L, S0=50 g/L/ X0= 1.0 g/LStep 2: batch fed with exponential flow (SF-800 g/L, μ= 0.1 h-1) until reaching X= 50.9 g/L;Step 3: batch fed with constant flow (F= 0.1 L/h) for 4 hours (induction phase with IPTG)Note: consider that the quasi-steady state is reached in both fed-batch stages.Extra data: YX/S = 0.4 gx/gs; μmax= 0.25 h-1; Ks== 1.0 g/L a) What was the cell concentration reached at the end of step 1?b) For step 3, considering that the substrate concentration in the feed was 1/4 of that used in step 2, what was the concentration of cells reached at the end of step 3?C) In terms of cell productivity, which of the three phases of cultivation was the most productive?